This is true, but we have many areas that received scarce 19th century immigration and are more European than all colonial regions of Latin America. The reason is that:
https://journals.openedition.org/nuevomundo/63251
You can download the PDF, it shows that in the colonial period Brazil received almost 3x more Iberian settlers than all Hispanic American countries combined. ~200.000-300.000 in Hispanic America vs ~800.000 in Brazil (some academic sources state 1 million).
So finding very Euro Brazilians with pure colonial stock is more common than elsewhere in Latin America. I've posted people with genealogy in Brazil for the last 200-300 years that are approaching 99% European.